CARVALHO, C.

DAVIDSON, E.

FIGUEIREDO, R. de O.

MARKEWITZ, D.

RCAAP - Repositório Científico de Acesso Aberto de Portugal

Tree growth soil response to P fertilization in a 24-year-old tropical forest on an Oxisol.

Repository Open Access to Scientific Information from Embrapa

C lose WindowTree growth and soil response to P fertilization in a 24-year-old tropical forest on anOxisolDaniel Markewitz, University of Georgia, dmarke@warnell.uga.edu (Presenting) Ricardo Figuieredo, EMBRAPA, ricardo@cpatu.embrapa.br Claudio Carvalho, EMBRAPA, carvalho@cpatu.embrapa.br Eric Davidson, The Woods Hole Research Center, eadavidson@whrc.org Mature, humid, low land tropical forests are generally considered to be P limited and to cycle Pefficiently. Whether this P limitation extends to younger secondary tropical forests that arere-grow ing on a large portion of the low land tropics, however, remains uncertain. As such,there is a knowledge gap between expectations of P limitation and direct observations ofsuch limitations. The objective of the current study was to fill this gap by fertilizing a naturalsecondary tropical forest that was 24-years-old. In February 1999 six 20x20 m plots wererandomly established in the secondary forest area of Fazenda Vitoria Ranch in Paragominas.After one year of pre-treatment tree measurement, 50 kg ha-1 of phosphorus as simplesuper-phosphate was supplied in January 2000 and 2001. Measurements over the follow ingsix years (age 25 to 31) demonstrated no increased tree growth. Over the seven years ofmeasurements (age 24 to 31) rates of biomass accumulation average 3.9±1.3 kg ha-1 yr-1.Most sequential P fractions (Resin, HCO3-Pi, NaOH-Pi, NaOH-Po, and 1M HCl) demonstratedsignificant increases shortly after fertilization and could account for nearly all the 50 kg ha-1of added P at each date. By January 2002, concentrations of P were declining in all poolsother than Resin P and by June 2006 concentrations had returned to initial levels.Interestingly, during this same period, P concentrations in all pools of the control plotsdeclined. P fixation capacity in the surface 0-20 cm layer is relatively low (~120 ug g-1) whilefixation increases to ~180 ug g-1 at 20-50 cm and approaches ~500 ug g-1 for all layersbelow 50 cm. This fertilization trial clearly demonstrated no growth limitation from low soil Pw ithin this secondary forest.Science Theme:  ND (Nutrient Dynamics)Presentation Type:  PosterAbstract ID: 82C lose Windowconverted by Web2PDFConvert.com

http://www.alice.cnptia.embrapa.br/alice/bitstream/doc/409328/1/ID39635.pdf

Tree growth soil response to P fertilization in a 24-year-old tropical forest on an Oxisol.

Abstract

Similar works

Full text

Available Versions

RCAAP - Repositório Científico de Acesso Aberto de Portugal

Repository Open Access to Scientific Information from Embrapa